108
FXUS63 KFGF 011805
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
105 PM CDT Mon Sep 1 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms are forecast late today
  through Tuesday.

- A seasonably strong cold front moves through Tuesday, bringing
  with it below average temperatures mid to late week.

&&

.UPDATE...
Issued at 1250 PM CDT Mon Sep 1 2025

Weak thunderstorms have recently developed in the James River
Valley with a report of a funnel in LaMoure County. SPC
Mesoanalysis 0-3km lapse rate and CAPE highlight the enhanced
stretching potential down there nicely. This is coincident with
what looks like a cloud line on which updrafts blossomed from.
This cloud line is likely due to some weak surface
convergence/vorticity as inferred by NDAWN`s wind observations.

There is some potential this type of occurrence could happen in
portions of the Sheyenne River Valley northward along the
western edge of the Red River Valley, with similar environment
currently being observed. Question will be whether or not enough
moisture and forcing can blossom updrafts along the area of weak
surface convergence. Should this occur, funnels may be possible
upon the initial developing phase of any updraft/convection.

While unlikely, these funnels may briefly touchdown. Will
monitor the environment and potential for these to occur in our
area. If conditions look more likely that funnels will develop,
will message this potential with a Special Weather Statement.

UPDATE
Issued at 1035 AM CDT Mon Sep 1 2025

Any isolated fog has since dissipated. Today will be the last
summer-like day for much of the area (namely those north of the
(I-94 corridor) for some time with the strong cold front still
progged to move through the area late tonight into the day
Tuesday.

Latest morning high resolution guidance indicates there is a
medium chance for widely scattered showers and thunderstorms
across the area. Sufficient moisture within the region (dew
points well into the 60s) and instability on the order of 1000
J/kg will amid weak upper support as seen on water vapor imagery
lends some confidence in this possibility. Severe weather is not
anticipated from this activity given the lack of
kinematics/shear.

UPDATE
Issued at 640 AM CDT Mon Sep 1 2025

Fortunately any fog has remain isolated and centered around
Gwinner/Forman ND. Otherwise have a narrow band of high clouds
moving east ahead of an upper level short wave trough which will
move thru. No precipitation in the area besides a couple
t-storms near Brandon MB.

Will maintain the grids and forecast as is which is dry thru
midday.

&&

.DISCUSSION...
Issued at 346 AM CDT Mon Sep 1 2025

...Synopsis...

An upper level trough, short wave, in southern Saskatchewan is
moving into southwest Manitoba. Isold showers and a t-storm with
this wave in western Manitoba. This short wave trough will move
east and be over the Red River valley at 00z Tue. High temps
today 75 to 80 will be enough with cooler air aloft with short
wave trough to generate 700 to 1200 j/kg MUCAPE and give at
least a low chance for a few showers or t-storms mid afternoon
into the evening. 0-6km bulk shear in the 30 kt range would
support a possibility (10 pct chance) for isold strong storms to
form in eastern ND mid to late aftn with risk of small hail.

Upstream is a cold front that is moving south thru Manitoba, but
this cold front will generally wait til the main 500 mb wave
drops south from northwest Canada Tuesday, with cold front
passing south thru the area Tuesday daytime, reaching far
southeast ND and west central MN at peak heating. MU CAPES 1000
to 1400 j/kg range and bulk shear 35 kts may be enough to
generate strong or severe storm near the MN/ND/SD border area
(20 pct chance severe). Though a tad higher chance does appear
to be just south of our forecast area. Day 2 SPC has far south
fcst area in marginal risk Tues aftn. But this tied to timing of
front southward, and its possible any isold severe threat is
more south.

Cooler airmass moves in in full force Tues night and Wed as
upper level short wave drop south into the northern valley 12z
Wed and then becomes an upper low in MN Arrowhead region
Wednesday afternoon. Significant cooling with highs Wed mid 50s
to low 60s along with a gusty north wind to 30 mph in E ND/RRV and
cloud cover and a chance for showers in NW MN. Clearing works
in Wednesday evening and night and will determine low temps with
fcsts low temps by Thu AM in the mid 30s in NW MN where frost is
possible.

Fast on its heels is another short wave that will drop quickly
southeast Thursday, with ECMWF/GEM/ICON much wetter than the
operational GFS and data used from the NBM (national model
blend). High pressure moves in Friday into Saturday with Friday
night and Saturday night seeing lows in mid 30s in areas of NW
MN where frost is possible.

Both periods the NBM shows a 10 pct chance of below 32F Park
Rapids and Langdon.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1250 PM CDT Mon Sep 1 2025

VFR conditions are forecast through at least 09Z before a cold
front begins to sweep through the region bringing IFR to MVFR
ceilings. There is also potential for thunderstorms to impact
aviation this afternoon and Tuesday.

Winds will be generally out of the south and southwest this
afternoon into early evening, before turning more northerly
behind the passing cold front. This cold front is not
anticipated to bring strong wind gusts. Timing of the frontal
passage is included within all TAFs. However, sites most likely
to be impacted by IFR/MVFR ceilings before 18Z include KDVL,
KGFK, and KTVF.

While widely scattered thunderstorms are expected within the
region this afternoon and Tuesday, it remains unclear whether or
not thunderstorms will impact TAF sites based on uncertainty in
coverage of thunderstorms. Should storms move over TAF site, it
could bring gusty erratic winds between 35kt-50kt and small hail
in addition to lightning.

Fog is not anticipated at any TAF site tonight/Tuesday morning
due to elevated winds.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

UPDATE...CJ/Riddle
DISCUSSION...Riddle
AVIATION...CJ